1. Field
The invention is in the field of clamps for connecting flexible hoses to hose fittings and in the field of couplings for connecting items together.
2. State of the Art
There are various clamps currently available for clamping the ends of flexible hoses to hose fittings, such as clamping the ends of automobile radiator hoses to the receiving collar for such hoses attached to the radiator. Most clamps include a metal band which fits about the outside of the hose and has some type of screw mechanism for tightening the clamp about the hose to thereby tighten the hose about the receiving collar. This secures the hose in place and prevent leaks. Some clamps are merely made of a spring metal and have a normal diameter small than the hose to be clamped. A special tool is used to force the clamp to a larger diameter to slip over the hose and when in position, the clamp is released and the clamp tightens about the hose.
In joining items together such as shafts or pipes, sleeves are sometimes used to surround the end of each item and hold the items in position relative to one another. With shafts, a resilient sleeve is sometimes used with the respective shaft ends to be joined forced into the sleeve thereby stretching it to a degree whereby the ends of the shafts are held tightly by the sleeve. With items such as pipe, sleeves are placed over the ends of adjacent lengths of pipe either by means of mating threads in the pipes and sleeve or by means of glue on the ends of the pipes and the interior of the sleeve.
Heat shrinkable material is currently used for covering electrical connections and generally takes the form of a homogenous sleeve of such material which is slipped over a wire before the connection is made. After the connection is made, the sleeve is slid over the connection and then heated so that the sleeve shrinks to tightly cover the connection. While such material works well to cover and seal such a connection, the compressive strength of the heat shinkable sleeve is usually small. Heat shrinkable tape, which is also commercially available, has the same problem of compressive strength. Neither the commercially available heat shrinkable sleeves nor the heat shrinkable tape is suitable for compressing tubing to secure it to tubing fittings or, generally, to secure various items together. U.S. Pat. No. 3,315,986 discloses the use of a homogeneous heat shrinkable sleeve as a clamp for flexible hose or pipes and U.S. Pat. No. 3,565,116 shows a homogeneous sleeve of heat shrinkable material used as a cover and reinforcement for a hose connector. While there are some materials which in the form of a homogenous sleeve can exert high compressive forces upon being subjected to heat and shrinking, such materials are expensive, have a small percentage of shrinkability, and have to be heated to undesireably high temperatures of up to about 500.degree. F. or more for shrinking to occur. The use of homogeneous sleeves of heat shrinkable material for clamping and connecting purposes has not been widespread.
It would be desirable to be able to get high compressive forces using relatively low cost materials which shrink at relatively low temperatures.